Submillimetre maps of the edge-on galaxy NGC 891

Abstract

Broadband continuum images of the edge-on galaxy NGC 891 at 850 and 450 microns are presented. These images are qualitatively very similar to the 1300 micron and CO images obtained by others. With respect to the 850 micron continuum, CO is strongest in the socalled `molecular ring', and weakest at the largest radii sampled. Inside the molecular ring, the CO/850 micron ratio is somewhat less than in the ring, but higher than in the remainder of the disk. The integrated far-infrared emission from NGC 891 is dominated by small particles shortwards of 100 microns. Longwards of 100 micron, the emission can be equally well fitted by a single population of large dust grains at 21 K, or a bimodal population of grains at temperatures of 18 K and 27 K. The circumnuclear disk is at a temperature of at least 50 K, and probably much higher.